Land Recent QUIC Changes until 03/27/2015

Land Recent QUIC Changes until 03/27/2015

Add comment for QuicFramer::AppendPacketHeader. Correct/improve DLOG output. Clean up problems found by clang_tidy.

Merge internal change: 89724433
https://codereview.chromium.org/1047493003/

Fixed header ordering, missing override/explicit keywords. Nothing to see here.

Merge internal change: 89622231
https://codereview.chromium.org/1047493002/

Always build a QuicSecureConfigUpdater at startup.

Merge internal change: 89604435
https://codereview.chromium.org/1047483002/

Remove the using_pacing argument from QuicSentPacketManager::SetFromConfig because it's always true.

Merge internal change: 89599305
https://codereview.chromium.org/1048493002/

Pass QuicCryptoServerConfig by pointer instead of reference.

QuicCryptoServerStream was storing const reference to the config, which
makes the interface bug-prone because it's not clear for the caller
that the config must outlive the stream.

Merge internal change: 89542072
https://codereview.chromium.org/1048483002/

Cache the value of GetMaxPlaintextSize in QuicPacketCreator.  No functional change.

Saves 0.68% in GFE QUIC loadtests.

Merge internal change: 89532959
https://codereview.chromium.org/1046523002/

Remove thread race conditions in two tests.  No change to production code.

Merge internal change: 89510581
https://codereview.chromium.org/1047453003/

Remove QuicFramer::encrypter, because it's a test-only method.

Merge internal change: 89499341
https://codereview.chromium.org/1046513002/

Review URL: https://codereview.chromium.org/1037403004

Cr-Commit-Position: refs/heads/master@{#322716}